Question: $ { {-2} \times \left[\begin{array}{rrr}{4} & {1} & {2} \\ {3} & {2} & {0}\end{array}\right] = {?} } $
Explanation: To multiply a matrix by a number, multiply each item of the matrix by the number. ${\left[\begin{array}{rrr}{-2}\times{4} & {-2}\times{1} & {-2}\times{2} \\ {-2}\times{3} & {-2}\times{2} & {-2}\times{0}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rrr}{-8} & {-2} & {-4} \\ {-6} & {-4} & {0}\end{array}\right]}$